KR102534130B1 - Dome for surveillance camera - Google Patents

Abstract

A dome for a surveillance camera includes an at least partially transparent spherical portion 110, a front transition portion 116, a rear transition portion 112 and a side transition portion. All transitions extend into the peripheral plane 106, and the tangent T1 to the spherical portion 110 connected to the front transition portion 116 is about the normal N1 to the peripheral plane measured in the plane of symmetry. The tangent T2 to the spherical portion 110, having an angle α, connected to the back transition portion 112 is equal to the normal N2 to the surrounding plane 106 when measured from the same plane and the same direction as the angle α. has an angle β to Angle β is greater than or equal to angle α.

Description

Dome for surveillance cameras {DOME FOR SURVEILLANCE CAMERA}

The present invention relates to domes for monitoring cameras, such as surveillance cameras.

Domes have been used for monitoring cameras for decades. The dome has the dual purpose of providing a waterproof housing for cameras placed inside the dome, while allowing images to be acquired through the dome. The portion of the dome where the camera collects images must have adequate transparency in the wavelength range used during acquisition. For most applications, this corresponds to a visually transparent dome, but if the wavelength region is in the near infrared (NIR), or infrared, or other wavelength region outside the visible spectrum, the dome may be visually opaque. In some cases, the material used for the dome may be colored, coated, or otherwise treated to obstruct the view to the camera. Because such an obstruction makes it more difficult for an individual to see the current direction of a camera placed therein (and thus more difficult to avoid being imaged by the camera).

A disadvantage of a dome over a flat window is that light (radiation) outside the dome is refracted differently by the dome depending on which part of the dome it passes through (considering the set of parallel rays approaching the camera). This causes an optical distortion of the image that users most often want to correct. For this reason, spherical domes are the most common design and have the advantage of uniform distortion. However, since the optical center of the camera is located at the center of the spherical dome, the optical conditions must be the same regardless of the camera's current orientation.

The dome's optical requirements regarding transparency and shape make it a relatively expensive component. Also, the dome will obviously end somewhere, and there is a problem with more optical distortion at and around the edge of the dome. A way to avoid these optical distortions may be to use a more complex design of the dome, which often results in a more complex manufacturing process. That is, while increasing the performance of the dome, the cost also increases. Its manufacture may include a more complex molding process including an increased number of mold parts and/or post molding steps such as fusion of two or more dome parts to form a final dome.

One proposed dome arrangement is presented in patent application KR1020100121765A, and an arrangement in which the dome is fastened in an inclined manner, similar to the arrangement of FIG. 6 of the present application, should consequently be regarded as prior art.

The present invention aims to alleviate some of the problems of existing domes by providing a uniquely shaped dome that allows for both an improved field of view and a simplified manufacturing process compared to current domes with such an improved field of view.

It is an object to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages of the art, singly or in any combination, and to at least partially address the above-mentioned problems.

To this end, the present invention relates to a dome for surveillance cameras. The dome includes an at least partially transparent spherical portion, a front transition portion, a rear transition portion, and side transition portions connecting the rear transition portion and the front transition portion on either side of the dome. Also, all transitions extend from the spherical part to a common peripheral plane, and the tangent to the spherical part connected to the front transitional part has an angle α > 0° with respect to the normal to the peripheral plane when measured from the plane of symmetry, and A tangent to a spherical part connected to a transition part has an angle β with respect to the normal to the surrounding plane, measured in the same plane and in the same direction as the angle α. The dome is characterized in that the angle β is greater than or equal to the angle α, and neither the rear turning portion nor the front turning portion has an inclination exceeding the angle α.

The dome's ingenious design allows for an adequate field of view for cameras placed inside the dome, while allowing for an easy manufacturing procedure.

In one or more embodiments, the radial center of the spherical portion is moved relative to the peripheral plane in the direction of the spherical portion. Moving the radial center with respect to the surrounding plane provides space for the camera to be placed at or near the radial center so that the camera's view through the partially transparent spherical portion is consistent over the camera's various directional ranges.

The angle of the tangent to the rear transition portion is greater than β for the entire transition portion.

In one or more embodiments, the back portion is tangentially connected to the spherical portion to provide a smooth, seamless transition from the spherical to the straight shape. Not only is this shape visually appealing, but it can better transfer loads (e.g. impacts) from the spherical part to the surrounding part without creating concentrations of force in the way, for example, sharper bends or defined corners. there is.

In one or any embodiment, all outer surfaces of the dome are visible when the dome is viewed at projection angle α, which is another way of expressing that the dome has no undercut portions, and is another way to express the finished product in a mold. This means you can easily take it out.

In some embodiments the front turning portion, the rear turning portion, and the side turning portions all extend down to the circular periphery of the peripheral plane. The circular shape facilitates mounting and sealing to the base and rotates the dome with respect to the base and achieves a symmetrical design.

To further enhance the symmetrical appearance of the dome, in one or more embodiments, it is preferred that the side transition portions follow the same angle as the rear transition portion at their connection to the spherical portion.

In one or more embodiments, the front transition portion follows an angle θ with respect to a tangent to a spherical portion connected to the front transition portion, where θ is at least 90° measured in the same plane and direction as α and β. In this way, the risk of the front transition part blocking the view of a camera placed inside the dome is reduced. The rear transition part and the side transition part may preferably have a similar shape to increase the symmetry of the design, but the front transition part will have a shape that conforms to other design rules where function is paramount.

It is preferred that the angle θ exceeds 90° to accommodate an extended field of view to ensure a full field of view for cameras placed inside the dome.

For symmetry, in at least one embodiment, it is preferred that the connection between the rear turning portion and the side turning portion for the spherical portion follow the same height relative to the peripheral portion.

In one or more embodiments, the side transition portions, the front transition portion and the rear transition portion define the shape of an inclined cylinder corresponding to the most basic shape that meets the criteria of the present invention. In a more sophisticated embodiment, the rear transition part and the side transition part define a frustoconical shape, again emphasizing the aspect and importance of symmetry in monitoring camera applications.

A further scope of the applicability of the present invention will become apparent from the detailed description given below. However, since various changes and modifications within the scope of the present invention will become apparent to those skilled in the art from this detailed description, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are provided for purposes of illustration only.

Accordingly, it should be understood that the present invention is not limited to the specific components of the device described or the operation of the method described. This is because such devices and methods may vary. In addition, it should be understood that terms used herein are only for describing specific embodiments and are not intended to be limiting. It should be noted that, as used in the specification and appended claims, the singular expressions "above" and "the" mean the presence of one or more elements unless the context dictates otherwise. Thus, for example, reference to “a unit” or “the unit” may include multiple devices and the like. Also, “comprising”, “including” and similar phrases do not exclude other elements or steps.

This and other aspects of the present invention will now be described in more detail with reference to the accompanying drawings. The drawings are not to be considered limiting, but instead are used to explain and understand. As shown in the drawings, the sizes of layers and regions may be exaggerated for illustrative purposes and are thus provided to illustrate a general structure. Like reference numbers refer to like elements throughout.
1 is a perspective view of a dome according to a first embodiment of the present invention.
2 is a schematic cross-sectional view of a dome according to a first embodiment of the present invention.
3 is a cross-sectional view of a state in which a camera is disposed inside a dome according to a first embodiment of the present invention.
4 is a perspective view of a transparent portion of a dome that can be used for a dome according to the first embodiment.
5 is an exploded view of other components that may be used in domes according to first or other embodiments of the present invention.
6 is a schematic cross-sectional view of a dome according to a second embodiment of the present invention.
7 is a schematic cross-sectional view of a dome according to a third embodiment of the present invention.

The present invention will now be more fully described below with reference to the accompanying drawings in which presently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided for thoroughness and completeness, and to fully convey the scope of the invention to those skilled in the art.

The dome of the present invention, an embodiment of which is shown in Figure 1, has a simplified molding process and a shape that facilitates proper viewing for a camera mounted inside the dome. It can be noted that although Fig. 1 shows one embodiment, the following text will contain information about parameters that can be changed for the realization of further embodiments. The dome 100 has a front surface 102 and a rear surface 104, and has a shape symmetric about a central vertical plane (the plane shown in FIG. 2). Dome 100 is designed to house a camera (not shown) in the usual manner of a dome camera, the area of the dome over which the camera is expected to acquire images is spherical (the area of wavelengths to be captured by the camera, typically visible) It is transparent to rays and near-infrared rays). The dome extends down to the peripheral plane 106 and is connected to the base during assembly. The perimeter 108 is circular in the illustrated embodiment, which is practical since the dome will be designed to rotate with the camera and will increase the symmetry of the dome 100 when viewed from different angles. The front face 102 forms part of a spherical portion 110 extending to the rear face 104, the rear transition portion 112 connecting the spherical portion 110 with the periphery and the rear transition portion forming the side transition portions on both sides. 114 to provide a transition to the peripheral plane 106 as well as a connection back to the front. There is also a front transition area 116 that has a different shape than the rest of the transitions (rear transition portion 112 and side transition portion 114) to enable the full camera view. As discussed below, the dome may be formed from a single component or from multiple components in a multi-component molding process or multi-step molding process.

Temporarily leaving FIG. 1 and referring to the schematic diagram of FIG. 2 to better explain how this effect is achieved. FIG. 2 is a diagram showing the shape of the dome 100 basically in the plane of symmetry described above. In situations where the dome is asymmetric for any reason, the plane of symmetry can be transformed into the center plane of the spherical part. Although exact names are not given for simplicity, the same reference numbers are used to refer to the parts. For example, instead of "region", the corresponding number is used to denote "segment" in FIG. 2 (which is a sectional view, not a perspective view). In this plane the dome consists of three working segments. The first working segment is a circular arc 110 corresponding to the middle segment in later embodiments. This arc 110 will allow a camera with imaging capability at the center of the arc (as is typical for dome cameras) to maintain an undistorted (or at least equally distorted) field of view over the range of tilt angles. . At the front end of the arc there is a front transition segment 116 extending from one end of the arc 110 to the periphery 108, and at the rear end of the arc a rear transition segment extending from the other end of the arc to the periphery 108 ( 112), and the perimeter is located in the perimeter plane. Worth mentioning, the surrounding plane is just an abstraction to better understand the dome shape. In the final dome camera product, the dome is attached to a base that serves as a platform for the necessary electronics and mechanics in most situations. Examples of this exist sufficiently in the prior art for the interested person to examine in more detail, but since the present invention mainly concerns the shape of a dome, it will not be further discussed here. Obviously, "before" and "after" could be replaced with "first" and "second", the words simply being used to aid understanding of the schematic diagram. A first tangent line T1 to the arc 110 may be defined where it connects to the front transition segment 116, and a second tangent line T2 to the arc 110 connects to the rear transition segment 112. can be defined where The first and second tangents T1 and T2 are both oblique to the perimeter plane and inclined in the same direction with respect to the normal to the perimeter plane. The effect of the tilt is that, when looking through the front of the dome (in embodiments where the peripheral plane is a horizontal plane such as the ceiling), a camera placed inside the dome obtains a field of view that extends beyond the horizon. It is the effect that the geometric center C of the arc segment (ie the center of the circle of which the arc segment forms a part) is offset from the peripheral plane 106 in the direction of the arc segment 110 that gives rise to this slope of the first tangent line.

Thus, it has been described how the shape of the dome facilitates proper viewing in at least one dimension and the ensuing effects associated with the molding process. This effect is closely related to the angle associated with the tangent. The first tangent is inclined at an angle α with respect to the normal N1 of the surrounding plane and the second tangent is inclined at an angle β with respect to the same normal N2 (equivalent in the sense “parallel to N1”). According to the invention, these angles can be equal or the angle β can be greater than the angle α. Also, no part of the front or rear transition segment should be inclined at an angle greater than the angle α measured in the same plane. In this way, there will be no undercut portion of the dome 100, which ejects (or demolds) the molded dome from the mold cavity when produced by molding (e.g., injection molding or compression molding). ) means that there are no obstacles. As a result, the criterion for an arc must not exceed a semicircle (i.e. less than 180 degrees), and the corresponding sphere may not be more complete than a hemisphere. Another way of expressing the criterion defines that all surfaces of the dome must be visible or at least not hidden when viewed at projection angle α (or larger angles), and also that a mold without undercut parts can be achieved.

In particular, as is clear from the discussion of projection angles and visibility, the criterion established for the plane of symmetry also applies to the other planes of the dome in that there can be no undercuts. The specific values for α and β can and will vary for other sections if present (small sections parallel to the plane of symmetry and close to the periphery of the dome, and containing essentially only cuts from the side connecting parts, i.e. frustoconical sections). consider). There are two direct ways to define the angle, and the use of a plane of symmetry and a section parallel to the plane of symmetry may be appropriate when discussing, for example, the properties of the spherical portion of the front of the dome. For other parts of the dome, it may be more appropriate to refer to the section of planes orthogonal to the peripheral plane and extending through the centerline of the dome, hereinafter referred to as “radial planes”. The centerline is orthogonal to the perimeter plane and extends through the geometric center C. The general condition of not creating an undercut portion still exists for these radial planes, but as can be seen from the drawing this is a less critical issue. Mainly because the spherical part and the transition part do not need to be optimized with respect to the camera view through the dome.

The rear transition segment 112 is preferably connected to the arc segment at an angle to the second tangent T2 to provide a continuous transition in which the effect of load focusing is minimized (compared to a situation where the two segments meet at a more pronounced bend). .

Figure 2 also includes an angle θ representing the angle of a portion of the front transition segment with respect to tangent T1. The angle θ is preferably 90° or more. That is, it is preferable that the aforementioned portion has an inclination corresponding to or more inclined than the extended radius extending through the center C. In this way, the field of view of the camera placed inside the dome can be taken into account so that the front turning segment 116 does not block the field of view. This feature can be useful in many different setups (dome and camera combinations), but is not essential to the present invention itself. Under normal circumstances, the shape of the front transition segment (and front transition portion) should only provide a transition between a spherical portion and a peripheral portion, and in many embodiments preferably a transition to a circular peripheral portion. The shapes illustrated in the drawings of this application are also driven by the desire to maximize rotational symmetry as much as possible, which means that the portion of the front transition segment closest to the peripheral portion should have a shape similar to that of the rear transition portion in that position. (e.g. along the same angle in the radial plane). Since the shape of the aforementioned portion (discussed in relation to angle θ) is preferably set by the field of view of the camera, the same is true for the transition point between the spherical portion and the front transition portion (i.e., this point is preferably set by the camera's field of view). set by the field of view), subject to the condition that the angle θ is greater than or equal to 90°.

Another effect of the dome shape associated with molding is that it has a designated front and a designated back, which is an added bonus. The injection point (essentially the molding process) can be optimized to provide good optical quality at the front of the dome, but will be less critical in other parts of the dome.

Leaving the two-dimensional view of FIG. 2 the drawing becomes a bit more complex, and the intended use of the dome can be explained to better describe the structural parameters. This will be done with reference to FIG. 3 . Figure 3 is a cross-section similar to Figure 2, but of a more complete embodiment with a schematic camera disposed within the dome. Apart from the components of FIG. 2 , FIG. 3 also includes a camera 118 . Camera 118 obviously includes imaging optics, and beams 120 and 122 represent how the field of view may range, for example as an effect of different zoom settings. In some dome cameras, the camera can pan and tilt freely under a static dome. In this case, the dome must be perfectly symmetrical and is generally a hemispherical dome. However, for purposes of the present invention, camera 118 will be allowed only by tilting relative to dome 102 (i.e., moving in the plane illustrated in FIG. 2), and in most embodiments panning (i.e., panning) will not be allowed (i.e. rotation in the horizontal direction is not allowed), at least not to a large extent. During panning, the dome moves with the camera so the camera does not pan against the dome. The effect is that in some embodiments the intermediate segment 110 need only have a defined shape in a small area extending on each side of the centerline. The dimensions of this “small area” will be defined by the field of view (which can also be defined as the field of view) of a camera 118 placed in the dome, which in practical applications will be defined by the camera inside the dome, indicated by cone 122 in FIG. 3 . will be defined as the maximum viewing angle for While the middle segment 110 has already been defined as following an arc in one direction, the middle section follows the same arc (an arc of equal radius) in all other directions due to symmetry and the need for minimized and consistent image distortion. That is, the middle portion may be a cutout of a sphere. This is shown in FIG. 4 and describes the shape of the middle segment 110 in all dimensions.

사이) 투영에서 모든 표면이 보여야 한다. 또한, 도 4의 예에서 전면 전환 부분(116)이 카메라의 시야를 방해하지 않도록 어떻게 형성되었는지, 즉 어떻게 주변부(106)를 향해 연속적으로 경사져 있는 지를 볼 수 있다.FIG. 4 also shows the respective shapes of the rear transition portion 112 and the front transition portion 116 . These features are less important because the camera field of view is designed to block access to these areas (meaning that distortion in terms of refraction is not a factor to consider). The main criterion is that there should still be no undercuts. That is, along (or at least with α) the angle α in the plane of symmetry (mirror plane) of the dome.

between) all surfaces must be visible in the projection. Also in the example of FIG. 4 it can be seen how the front transition portion 116 is shaped so as not to obstruct the view of the camera, ie how it slopes continuously towards the periphery 106 .

The rear transition portion 112 can also have any shape within set parameters. However, for simplicity and convenience, a frustoconical shape may be suitably given, for example, extending in the second tangential direction so that a smooth transition between its parts can occur.

Additionally, in most embodiments the perimeter 106 will form a circle to increase symmetry, such that both the front and back transition segments/portions extend from the middle segment/portion to another portion of the same circular perimeter 106. means it will be The circular shape of the periphery is not a necessary feature, but apart from the increased symmetry, it has advantages related to how it simplifies rotational movement relative to the base on which the dome can be placed.

An additional criterion relates to the specific use for which the dome is intended, namely surveillance. In the case of a dome camera, there is an added benefit if the orientation of the camera inside the dome is ambiguous. Since the current dome is asymmetric in that the front of the dome is different from the back and sides, the front of the dome and hence the possible orientation of the camera may be clearer, which can be clearly seen in FIG. 1 . For this reason, the shape of the rear transition segment/portion can mimic all around the camera in the side transition segment, i.e. all parts that are not front transition segments (not even the middle segment), which is also shown in Figure 1 (again, see Figure 1). This will correspond to a front turning portion and a side turning portion having the same shape (eg the same angle in the simplest embodiment) when viewed in their respective radial planes.

As can be seen in Figure 1, what can be called a viewing window is formed in the front of the dome where the front transition part connects the middle segment to the periphery and the rear transition part (or an area of the same shape as the rear transition segment). Although the part where the front transition segment connects to the periphery has been described, the shape of the sides of this window is also defined by the expected field of view of the camera placed within the dome. More specifically, in Figure 1 for example, these sides will slope outward to minimize the risk of obstructing part of the field of view.

As shown and defined so far, the entire dome can be easily formed in one piece in a two-piece mold with easy demoulding.

5 is an exploded view of a dome according to another embodiment of the present invention. This embodiment could also be formed with a two-part mold, but would be a multi-component molding. The finished dome consists of three different parts, two of which can be placed in the mold before injecting the material for the transparent part.

The two side parts 124 are essentially IR-transparent parts that are visually opaque but allow IR-radiation from an IR-illumination source disposed within the dome to illuminate the camera's field of view. It is clear from FIG. 5 that these two parts also include parts of the spherical part. Additional parts can be added in a similar way if needed. All parts can be formed from the same base material, and additives define the properties of the different parts.

The two side parts can be formed in the first or second step of a two-step molding process when the dome is manufactured, which reduces handling of the individual components at the cost of a slightly more complex but still simple molding process. The materials used for the different parts must, to the extent necessary, be compatible so that they can be fused together in the molding process. In the simplest example, all components are made from the same basic material, polycarbonate plastic, and additives provide the desired properties. Any material used in camera domes today, such as polycarbonate plastics, acrylic plastics, etc., may be a viable option of the present invention, except that the material used itself is not an essential part of the present invention. The material of the spherical part must be transparent in the relevant wavelength region, must be a viable choice, and can be molded to take full advantage of the shape. Injection molding is one possible method preferred for the illustrated embodiments of the present invention, but is not excluded as compression molding, blow molding or other molding methods may all include a demolding step. In an alternative embodiment, side parts may be prefabricated and placed in a mold. The mold is then closed and the material in the transparent part is injected. The molding process fuses all parts into a single component, simplifying the assembly of the final product and improving the sealing properties of the same part.

Obviously, the side pieces 124 can be eliminated from the process as individual components, meaning that the entire dome can be molded in a single step and with a single material. In addition, certain properties for other parts of the dome may be obtained during post-molding processes such as coating, painting, abrasion, etching, and the like.

6 is a schematic diagram of a basic version of the dome of the present invention. Basically, it consists of two geometric shapes. A sphere placed at one end of a cylinder, with both shapes the same diameter. The cylinder is cut at an oblique angle along the plane. Compared to the more refined embodiment, this simplified embodiment will have a more asymmetrical shape and its circumference will not be circular.

In Fig. 7, the cylinder of Fig. 6 has been replaced with a frusto-conical part as an intermediate development from a general idea to a valid product.

Claims (6)

A dome for a surveillance camera, the dome comprising an at least partially transparent spherical portion, a front transition portion, a rear transition portion, and side transition portions connecting the front transition portion and the rear transition portion on both sides of the spherical portion; , wherein the front turning portion, the rear turning portion and the side turning portions each extend in a common circular peripheral plane;
wherein the tangent to the spherical portion at which the spherical portion is connected to the front transition portion has an angle α > 0° with respect to the normal to the peripheral plane, measured in the plane of symmetry and away from the radial center of the spherical portion. have
A tangent to the spherical portion at which the spherical portion is connected to the backside transition portion has an angle β with respect to the normal to the peripheral plane when measured in the same plane and in a direction toward the radial center of the spherical portion, where the angle β is greater than or equal to the angle α,
The dome for surveillance cameras, characterized in that the side transition portion has the same height as the rear transition portion with respect to the peripheral plane, such as defining a frustoconical shape. The dome according to claim 1 , wherein a radial center of the spherical portion is moved relative to the peripheral plane in the direction of the spherical portion. delete delete The surveillance camera according to claim 1, wherein an angle θ between the front turning portion and a tangent to the spherical portion at which the spherical portion is connected to the front turning portion is 90° or more when measured in the same plane and direction as α. dome. 6. The dome of claim 5, wherein the angle θ is greater than 90° to accommodate an expanded field of view of a camera disposed inside the dome.

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